docs: def manual_seq_mapping(self, gene_to_seq_dict, outdir=None, write_fasta_files=True, set_as_representative=True):
          """Read a manual input dictionary of model gene IDs --> protein sequences. By default sets them as representative.
  
          Args:
              gene_to_seq_dict (dict): Mapping of gene IDs to their protein sequence strings
              outdir (str): Path to output directory of downloaded files, must be set if GEM-PRO directories
                  were not created initially
              write_fasta_files (bool): If individual protein FASTA files should be written out
              set_as_representative (bool): If mapped sequences should be set as representative
  
          """
          if outdir:
              outdir_set = True
          else:
              outdir_set = False
  
          # Save the sequence information in individual FASTA files
          for g, s in gene_to_seq_dict.items():
              gene = self.genes.get_by_id(str(g))
  
              if not outdir_set and write_fasta_files:
                  outdir = gene.protein.sequence_dir
                  if not outdir:
                      raise ValueError('Output directory must be specified')
  
              manual_info = gene.protein.load_manual_sequence(ident=g, seq=s, outdir=outdir,
                                                              write_fasta_file=write_fasta_files,
                                                              set_as_representative=set_as_representative)
              log.debug('{}: loaded manually defined sequence information'.format(g))
  
          log.info('Loaded in {} sequences'.format(len(gene_to_seq_dict)))